Fig. 1. Layout and physical diagram of a soliton optical frequency comb generation system. (a) The layout of the soliton optical frequency comb generation system. The system consists of: NI 6003: Data acquisition device; BPF: bandpass filter; PM: powermeter; FBG: fiber Bragg grating; TEC: thermoelectric cooler; 99/1: 99/1 optical splitter; 90/10: 90/10 optical splitter; NKT laser: OEM fiber laser, operating at 1550 nm; EDFA: erbium-doped fiber amplifier; 12 V power: power supply; orange lines indicate optical fibers, electrical connections are shown in green (digital) and black (analog). (b) The physical diagram of the soliton optical frequency comb generation system. i: NI 6003; ii: EDFA; iii: NKT laser; iv: packaged chip with TEC; v: 12 V power; vi: TEC.

Fig. 2. The logic codes and algorithm flowchart of the “one-button start.” The blue-colored part is for single-soliton generation, and the red-colored part is for addressing the multi-soliton state. The solid lines with arrows represent the successful approach, and the dashed line with the arrow represents the failed approach. P: PD voltage; X: output voltage.

Fig. 3. Schematic diagram and practical application of the feedback adjustment apart. (a) The logic codes and algorithm flowchart of the feedback adjustment part. (b) Spectrogram of the single-soliton state optical frequency comb produced continuously for 2 days. The frequency of the optical frequency recording is once every 60 s.

Fig. 4. Two situations of the PD voltage and spectrograms corresponding to specific positions. (a) PD voltage for normal generation of single-soliton state optical frequency combs. (b) When the laser frequency is blue-detuned, PD voltage is for the generation of the chaotic state. (c) Spectrogram of the junction of three zones. The numbers represent the one-to-one correspondence between the power and spectrum at each position. i: the chaotic state; ii: the multi-soliton state; iii: the dual-soliton state; iv: the single-soliton state.

Fig. 5. Successive generation of single-soliton states and chaotic states. (a) Generate 1000 times single-soliton states. (b) Generate 10 times single-soliton states. (c) Generate 100 times chaotic states. (d) Generate 10 times chaotic states. (e) Histogram of time statistics for 1000 single-soliton state generation.